Gas turbine engines, such as those which power aircraft and industrial equipment, employ a compressor to compress air that is drawn into the engine and a turbine to capture energy associated with the combustion of a fuel-air mixture. In an aircraft gas turbine engine a fan is frequently employed towards an axial, forward end of the engine for purposes of air intake. An inlet cap (also referred to as an inlet cone front segment) is located upstream of the fan. The inlet cap, which is composed of plies of composite material, is rotatably mounted to the turbine engine to affect the flow of air into the fan. Examples of inlet caps are described in United States Patent Application Publication Number 20070079920 A1 (hereinafter '920 publication), the contents of which are incorporated herein by reference.
Inlet caps require periodic maintenance to address wear incurred by the inlet cap. Such wear can be caused, for example, by objects (e.g., birds) striking the inlet cap or by particulate matter causing abrasion to exterior surfaces of the inlet cap. In addition, engine maintenance and service procedures can cause wear to the inlet caps.
An inlet cap typically includes lug slots. The lug slots are designed to receive a fastener to secure the inlet cap relative to the engine. The areas/regions of the inlet cap in proximity to the lug slots may be particularly prone to erosion/wear. For example, the fasteners are likely to be accessed during the maintenance/service procedures described above; wrenches or other tools may strike the area/regions of the lug slots during such procedures. In conjunction with another typical scenario, the fasteners may be overtightened which may have an impact on the integrity of composite material used to form the lug slot. Furthermore, in terms of orientation the areas/regions in proximity to the lug slots are substantially perpendicular to the airflow through the engine. In this respect, if an object strikes the inlet cap in proximity to the lug slots, any of the plies of material used in the formation of the inlet cap end up absorbing a substantial amount of the energy associated with the strike.
The techniques used in the repair of an inlet cap described in the aforementioned '920 publication are sufficient when the inlet cap is of a sufficiently large size. As the dimension of the inlet cap decreases, the areas of two adjacent/consecutive lug slots may begin to overlap in terms of their respective material plies.